1. Field of the Invention
This invention relates to a telescoping pneumatic spring having a stroking piston operatively mounted in a cylinder tube and normally capable of gas forced outward stroking movement form a starting telescoped position to an extended stop position and more particularly to a new and improved pneumatic spring controlling the swinging movement of an associated closure and incorporating an adjustable stop mechanism to vary the relative outward stroke of the piston and the open position of the closure to an infinite number of stop positions.
2. Brief Description of the Prior Art
Prior to the present invention, various pneumatic spring units have been devised for controlling the motion of automotive body closures such as hoods, trunk lids, lift gates and other access doors. In U.S. Pat. No. 3,938,793 issued Feb. 17, 1976 to Kapanis et al. for Pneumatic Spring With Stop Mechanism, a pneumatic spring of the piston and cylinder type is equipped with an internal stop mechanism which limits the outward stroke of the piston and rod relative to the cylinder to accordingly limit the movement of an associated trunk lid to a predetermined degree of opening. In U.S. Pat. No. 6,126,222 issued Oct. 3, 2000 to Nguyen et al. for Lift Gate Assembly, an auxiliary cable unit is utilized to limit the amount of opening of a lift gate whose opening is assisted by separate pneumatic springs.
While such prior art constructions may meet their objectives, some are difficult to adjust while others involve auxiliary stop units separate from the pneumatic spring. Accordingly, such constructions do not meet new and higher standards for straight forward and simplified construction providing improved control of pneumatic spring stroking particularly those used to advantageously assist physical effort in displacing doors and other closures to a wide range of predetermined stop positions. In sharp contrast to the prior art construction, the present invention overcomes the various disadvantages of the prior art and provides a basic and readily adjustable pneumatic spring that can be readily set to control the amount of travel of associated closures such as lift gates for vehicles to establish a wide range of positive stop positions in accordance with opening requirements.
It is a feature, object and advantage of this invention to provide a new and improved pneumatic spring for assisting the opening of access doors or other closures of vehicles which feature a built-in adjustable stop that can be readily adjusted to a wide range of stop positions to positively limit the extent of closure opening. With this construction, the closure can be set to an infinite number of convenient closure stop positions readily accessible by the person normally using the closure in accordance with their physique or range of motion capability.
It is another feature, object and advantage of this invention to provide a new and improved piston type pneumatic spring for use with access doors of vehicles featuring an adjustable stop on a cylinder tube and an associated dust tube with a fixed stop ring that provides a built-in tool for varying the stroke of the spring to fixed stops.